This invention relates generally to the field of helicopter-borne rescue hoist systems in which a malfunction-warning system is incorporated.
In the continued development of helicopter rescue hoist systems, one important problem has been the lack of a positive indication to the hoist operator when a malfunction has occurred, particularly in the traction sheave assembly portion of the overall hoist system. Such malfunctions may, for example, induce hoist cable slack, cable miswraps, and/or cable or total hoist system failure which could be detrimental or even fatal to the rescuee. Therefore, it becomes essential that the hoist operator be made immediately aware of precisely where a malfunction has occurred in the overall rescue hoist system, as for example, when there is slack in the hoist cable resulting in the fouling and/or snarling thereof. Of course, as a minimum, such malfunctions always result in cable damage sufficient to require the immediate replacement of the cable. Moreover, in an extreme case, catastrophic cable failure can occur which sometimes can also result in injury or even death to the personnel being rescued as noted hereinabove. Unfortunately, in a helicopter rescue hoist system under the most current development by the U.S. Government, a sheave warning light used therewith merely indicates whether or not electrical power is being applied to the traction sheave motor, and does not provide any indication of mechanical failures relating to the motor or traction sheave pulley assembly.
The unique warning light or malfunction-indicating alarm system of the present invention solves or, at least, substantially alleviates the foregoing problem by utilizing a torque-sensing mechanism to produce an effective, reliable, real-time and readily visible indication of any traction malfunction which could induce cable slack. In this regard, although the general concept of a torque sensing means is already broadly known, as is evidenced, for example, in U.S. Pat. Nos. 3,289,471 and 3,800,599, respectively issued on Dec. 6, 1966 and Apr. 2, 1974 to L. R. Maxwell and M. B. Goran, the torque sensing mechanism of the present invention is deemed to involve a new and improved combination that is integrated with a rescue hoist-traction sheave assembly in a novel and yet simplified manner, as will appear self-evident hereinafter in the following summary and detailed description.